It is widely known that easily accessible resources of fossil fuels are declining. In addition, the impact of the use of fossil fuels upon the environment has become increasingly apparent. As a result of this, it has become imperative that viable alternative energy sources are used as effectively and efficiently as possible. The use of turbines to capture the power of water flow, such as tidal, river and ocean current flows is becoming a viable source of alternative energy. The turbine equipment used to capture such water flow energy typically includes a rotor assembly connected via a drivetrain to a shaft driven power generator. The rotor assembly includes a plurality of rotor blades that are driven by the water flow, so as to turn an input shaft of the drivetrain, and hence the generator.
Existing turbine systems are arranged to operate at a nominal operating point, typically the power being generated. This operating point is chosen in order to balance power output requirements with the physical requirements of building the system. For example, it is possible to model and predict with some certainty steady state loading for a range of flow speeds and power outputs. This loading modeling is then used to determine the design and specification of the system components, for a desired operating point of the equipment, such that the components of the system that are able to deal with such steady state loading, and that are economically viable. The loading capabilities of the components are then typically uprated from this nominal design point, in order that transitional loading, such as that caused by waves or other turbulence, can be accommodated. This results in equipment that is able to withstand higher loading than is often experienced in practice.